Caster structure



C. R. NALLE CASTER STRUCTURE Feb. 28, 1950 Filed OOC. 18, 1945 PatentedFeb. 28, 195() UNITED sTATEs PATENT oEFlcE CASTER STRUCTURE Charles R.Nalle, Philadelphia, Pa.

Application October 18, 1945, Serial No. 623,030

4 Claims.

This invention relates to adjustable caster structures for articles offurniture and the like, for preventing rocking or distortion of sucharticles, or for correcting distortion thereof, 'as may arise fromunevenness of the floor or other surface on which an article of saidkind may be standing.

The adjustable caster structures or devices of the prior art, includingthose procurable on the open market, are normally of a complicatednature involving many parts, which increases the cost of manufacture,and consequently the cost to the ultimate consumer, materially,

The principal object of the present invention is to reduce the number ofparts of 4an adjustable caster structure to a minimum, for example,three relatively movable members, and to construct these elements in amanner whereby they may be manufactured and lassembled at a minimum ofcost, whereby the devices may be sold to the ultimate consumer at a verylow retail price.

In the accompanying drawings Fig. l illustrates the preferred form ofthe device of the present invention in side elevation, as installed in atable leg, etc. which latter is shown in vertical sectional elevation;

Fig. 2 is -a vertical sectional elevation as taken on the line 2-2, Fig.1;

Fig. 3 is a sectional plan View as taken on the line 3-3, Fig. 2;

Fig. 4 is a sectional elevation of two of the three relatively movableparts of which the device of the present invention is composed and asshown in Figs. 1 and 2, said two parts being illustrated as being in thecourse of assembling; and

Fig. 5 shows a wheel type caster which may be emplo-yed with the presentinvention.

` In the preferred form of the invention as shown in Figs. 1 to 4inclusive, two of the elements of the device of the present inventionare preferably composed of die castings.

The device, as shown in Figs, 1 to 4 inclusive, is composed of afloor-engaging element such as a conventional caster wheel, or a ball orbutton type glide A, a ferrule or socket B, and a captive nut C.

The hoor-engaging element A includes an ex ternally threaded Stem I,with diametrically opposite side portions thereof attened and disposedparallel to each other, as indicated at 2, 2; and with diametricallyopposite side portions 3,3, lying intermediate and alternating with theflat faces 2, y2, being of a segmental or arcuate nature, with square orV-shaped threads formed therein, the root circle 4 of said threads beingsubstan- 2 tially tangent to the fiat faces 2, 2 of said stem.

The ferrule or socket B includes a circular disclike head 5 and anaxially extending elongated neck 6 integral with one end thereof, saidneck being adapted to be inserted in a circular bore d formed in thelower end of a table or bed leg D etc.

The neck 6 is provided with an axial cavity I of the same cross sectionas the stem I, with opposite parallel fiat internal side faces 8, 8adjacent `and in Snuglysliding contact with the flat side faces 2, 2 ofthe stem I, and with intermediate arcuate internal side faces 9, 9adjacent and in snugly sliding contact with the arcuate faces 3, 3 ofthe stem I which constitute the outer surface of the interrupted ormutilated screw threads formed on the stem I.

The head disc 5 is provided on -an upper annular surface I0 thereof,which surrounds the neck 6, with a plurality of circumferentiallyspaced, axially extending prongs I I, I I, which are adapted to bedriven into or otherwise anchored in the lower end of the leg D toprevent rotation of the ferrule B within the leg cavity d, and toprevent accidential withdrawal of the neck 6 from said leg cavity.

The head disc 5 of the socket BI is also provided with a circumferentialannular or peripheral edge ange I2 which nts within an internal annulargroove I3 formed in the captive nut C.

The under surface I4 of the head disc 5 is flat and smooth and isadapted to bear on a similar smooth iiat bearing surface I5 formed inthe captive nut C.

The captive nut C is held against axial movement in one directionrelative `to the ferrule B by contact of the annular surface I5 of thenut C with the bearing surface I4 of the ferrule B; and in the oppositedirection by lan annular inturned flange or lip I6 formed on the upperend of said nut and overlying the upper annular surface I1 of thecircumferential ange I2 of the ferrule head 5.

The captive nut C is axially bored and internally threaded, as indicatedat I8, for cooperation with the segmental thread portions 3, 3 on thestem I; whereby, as the nut C' is rotated clockwise orcounter-clockwise, the stem I is moved axially to shorten or lengthenthe leg D.

As previously noted, the nut C and ferrule B are preferably made of diecastings with the annular lip or ange I6 of the nut C originallyextending axially in open ended cylindrical form, as shown at y in Fig.4, from one end of the threaded base portion of the nut, to form a cer.

tral concentric cavity :c in said one end thereof.

The nut C and ferrule B are assembled, as clearly shown in Fig. 4, byinserting the circumferentially flanged head of the ferrule in thecylindrical cavity of the nut C, after which the axially extending angey of the nut C is swaged radially inward over the top surface l1 of theannular peripheral flange I2 on the head disc 5, to form the inturnedflange or lip I6 and thereby forming the annular groove I3 in thecaptive nut C by which the nut C is retained in rotatable but axiallynon-slidable rotation to the ferrule B.

The caster structure of iny present invention is applied to an articleof furniture or the like by first forming a hole, like the bore daforesaid, therein to receive the neck 6 of the ferrulev or socket B.The stem l of the ioor-engaging element A is rst removed from thecaptive nut C, and the neck of the ferrule is inserted in the said holein the article to be supported until the ends of the prongs ll engagethe surface of the article surrounding said hole, whereupon a sharp blowdirected against the exposed lower face of the nut C will cause theprongs il to become anchored in the article. The stem l of theiioorengaging element is then reentered into the captive nut C, untilthe cooperating threads thereof are engaged, whereupon, turning of thenut or hand -wheel C will move the stern axially into the cavity 'i ofthe head 5 and neck ii, until the hoor-engaging element A is in adesired initial position with respect to the article.

Normally it would be cliflicult toalign the flat sides 2, 2 of the steml with the iiat sides 8, 8 of the head 5 at the lower end of the socketor ferrule B after the threads of the stem had caught with the threadsin the nut C, and to assist in this operation, in the present instance,the free end of the stem I is reduced in diameter at least to the rootdiameter of the threads and is devoid of threads for a distance greaterthan the length of the threaded bore of the nut C, as illustrated at 30.i

This plain end 30 functions as a lead in advance of the threaded section3 of the stem l to pass uninterruptedly through the threaded `bore ofthe nut C and to enter between the flat faces 8 supra, whereby a personassembling the floor-engaging elementrinitially with the ferrule orsocket B may feel his way in, it ybeinggunderstood that the plain end ofthe stem will enter the open end of the flat sided opening in theferrule head 5 before the threads on the stem l engage with the threadsin the bore of the nut C and thereby will guide the end of the stem intosaid opening, then by slight circular manipulation between the stem andthe nut the at sides of the stem can be readily aligned with the iiatsides of the opening in the head 5, after which the stem may be readilymoved in the ferrule by rotation of the nut C.

While the floor-engaging element A isshown as being of the iiat buttontype of glide, yit will be readily understood that this glide may bereplaced on the end of the stein l by any conventional type of roller orwheel such for example as the ball-bearing type as showndiagrammatically in Fig. 5, wherein a pair of ball races l3l and 32 aremounted on a reduced lower lend 33 of the stem therebetween, and whereinthis assemblage is held on the lower end of the stem by riveting thelower end of the stem over a washer thereon, as indicated at 35.

The lower race 32 carries a pair of spaced parl with a series ofanti-friction balls 34 I claim: 1. A caster structure composed solely ofa oorengaging element including an externally threaded axial stem havingat least one axial flat extending along the threaded portion thereof, aferrule including an elongated neck having an axial bore adapted toreceive said stem, at least one axial flat extending along said boreadapted to cooperate with the iiat on the stem preventing relativerotation but permitting relative axial movement between the stem andferrule, a disc-like head rigidly connected to one end of said neck, acaptive nut adjacent and axially aligned with said head and having 'aninternally threaded bore adapted to cooperate with the threads on saidstem for effecting relative axial movement between said stem and saidferrule, and a peripheral iiange on said head operating in acircumferential groove in said nut to allow relative rotation and toprevent relative axial movement between said nut and said ferrule.

2. A caster structure composed solely of a floor-engaging elementincluding an externally threaded stem having a pair of opposite axialflats cut therein, said ilats being tangent to the root diameter of thestem, a ferrule including an' elongated neck having a bore adapted toreceive said stein, a pair of opposite axial flats extending along saidbore adapted to cooperate with thev flats on the stem and preventingrelative rotation but permitting relative axial movement between thestem and ferrul'e, la captive mit rotatably mounted on one end of saidferrule and pro'- vided with a central internally threaded bore for'cooperation with the' threads on said stem for effecting said relativeaxial movement between said licor-engaging Aelement and said ferrule, a

f disc-like head forming part of said ferrule and rigidly connected toone end 'of said neck, and a series of circumfer'entally spaced prongssurrounding and spaced radially from the axismof said neck and extendingin va 'direetion parallel to said axis for securing said feriule againstife-l tation relative to an article of furniture andthe like to whichsaid caster structure is applied.

3. A caster structure composed solely of a' floor engaging elementincluding an externally threaded Aaxial stem having at least 'one axiallflat extending along the threaded portion thereof, a ferrule includingan elongated neck having an axial bore adapted to receive said stem, atleastcne axial iiat extending along said bore' adapted to cooperate withthe flat on the stern preventing relative rotation by'perinittingrelative axial movement between the stein and ferrule, and a captive nutrotatably mounted on one end of said ferrule and provided with a centralinternally threaded bore for 'cooperation with the threads on said stemfor effecting said relative axial movement between said floor-engagingelement and said ferrule;

4. A caster structure Vcomposed solely of ay vfloor-engaging elementincluding an externally threaded stem having a pair vof opposite axialiats cut therein, said iiats being tangent to the root diameter of thestem, a, ferrule including an elongated neck having'a bore adapted toreceive said stem, a pair of Iopposite axial flats extending along saidbore adapted to cooperate with the ats on the stem and preventingrelative rotation but permitting relative axial movement between thestem and ferrule, and a captive nut rotatably mounted on one end of saidferrule and provided with a central internally threaded bore forcooperation with the threads on said stem for effecting said relativeaxial movement between said floor-engaging element and said ferrule.

CHARLES R. NALLE.

REFERENCES CITED le of this patent:

Number Number UNITED STATES PATENTS Name Date Hartmann Dec. 4, 1928Nalle Sept. 27, 1932 Nalle Sept. 2,y 1941 Nalle Nov. 23, 1943 Nalle Jan.18, 1944 FOREIGN PATENTS Country Date France Apr. 22, 1920 Certificateof Correction Patent No. 2,499,277 February 28, 1950 CHARLES R. NALLE Itis hereby certified that errors appear in the printed specification ofthe above numbered patent requiring correction es follows:

Column 3, line 12, for the Word rotation read relation; column 4, line61, for "by permitting read but permitting;

and that the said Letters Patent should be read with these correctionstherein that the same may conform to the record of the cese in thePatent Oice.

Signed and sealed this 30th day of May, A. D. 1950.

[out] THOMAS F. MURPHY,

Assistant Uommz'saoner of Patents.

